Benthic foraminiferal assemblages of late Aptian-early Albian black shale intervals in the Vocontian Basin, SE France J. Erbacher 1 , W. Gerth, G. Schmiedl and Ch. Hemleben Institut fu Èr Geologie und Pala È ontologie, Universita Èt Tu Èbingen, Sigwartstraûe 10, 72076 Tu È bingen, Germany; 1 present address: Bundesanstalt fu È r Geowissenschaften und Rohstoffe, Postfach 51 01 53, 30631 Hannover, Germany Revised manuscript accepted 5 May 1998 Benthic foraminiferal assemblages were analyzed from three black shale intervals in the upper Aptian to lower Albian of the Vocontian Basin, SE France based on Q-mode principal component analyses. Variations in the distribution patterns of benthic foraminifera around these events suggest differences in the origin of the black shales. Differences between faunas of bioturbated marly and laminated black shale facies have been observed in the Niveau Paquier, Oceanic Anoxic Event (OAE) 1b and Niveau Leenhardt. Here, the faunal composition and plankton/benthos ratios suggest eutrophic conditions during the deposition of organic-rich sediments leading to black shales. No major variations have been observed in black shales of the upper Aptian Niveau Jacob. Benthic assemblages and low plank- ton/benthos ratios indicate mesotrophic conditions. Third order sea-level changes are believed to con- trol mainly the origin of the investigated black shale levels. # 1998 Academic Press Limited KEY WORDS: benthic foraminifera; black shales; Lower Cretaceous; Aptian; Albian; Vocontian Basin; France. 1. Introduction Deep-water benthic foraminifera and their habitats are in¯uenced by numerous factors such as nutrient ¯ux, bottom-water oxygenation and to a lesser extent by temperature and salinity. On the other hand, models proposed by Jenkyns (1980), Bralower & Thierstein (1984), Arthur et al. (1990), and Erbacher et al. (1996b) suggest that the deposition of middle Cretaceous black shales is controlled by nutrient supply and productivity in the upper water column and/or oxygen content in bottom waters. Therefore, benthic foraminifera can serve as a sensitive tool to provide a better understanding of the depositional history of black shales and the causes of anoxia in marine basins. Most studies of the in¯uence of Cretaceous black shale events on the evolution and distribution of benthic foraminifera have focused on assemblages from the Cenomanian-Turonian boundary interval [Oceanic Anoxic Event (OAE) 2] (Koutsoukos et al.; 1990; Tronchetti & Grosheny, 1991; Kaiho & Hasegawa; 1994; Coccioni et al., 1995; Kuhnt & Wiedmann, 1995; Peryt & Lamolda, 1996). In general, these authors observed that the interval preceding the maximum anoxia of OAE 2 is characterized by a stepwise decrease in the number of taxa; the anoxic peak of the event is often characterized by an absence of benthic foraminifera, and the interval above the anoxic event shows a gradual Cretaceous Research (1998) 19, 805±826 Article No. cr980134 0195 ± 6671/98/060805 + 22 $30.00/0 # 1998 Academic Press